The Genus Heterospathe (Palmae: Arecoideae) in the Philippines

Abstract

Heterospathe, an arecoid genus belonging to the subtribe Iguanurinae (Dransfield & Uhl 1986; Uhl & Dransfield 1987), is confined to the Solomon Islands, New Guinea, Micronesia, Moluccas and the Philippines (Map 1). The genus was established by Scheffer (1876) based on Heterospathe elata, originally collected from Ambon. There are about 32 species (Moore 1973; Uhl & Dransfield 1987) hitherto known in the genus varying from small, undergrowth, acaulescent palms to tall tree palms. The genus is generally regarded as largely Papuasian or East Malesian as most of its closest relatives occur there, but it has its westernmost limit in the Philippines. Heterospathe has been partially revised by Moore (1969, 1970) and a full emended generic description has been provided also by Moore (1969) and more recently by Uhl & Dransfield (1987). Beccari (1919a) and Merrill (1922) both listed four species of Heterospathe from the Philippines. Moore (1970) eventually referred back to Heterospathe all three Philippine species of Rhopaloblaste (Martelli 1934, 1935) which were originally described by Beccari (1909, 1919a, 1919b) in Heterospathe and Ptychoraphis. Moore (1970), however, did not make actual transfer combinations of two epithets owing to the need for further study of the species. Much earlier, Beccari in a paper edited by Martelli (1935) referred one species, Ptychoraphis cagayanensis, back to Heterospathe. There were, thus, eight species of Heterospathe known from the Philippines until recently. Intensive collecting in recent years of more complete herbarium material has revealed a much wider range of variation within Heterospathe and has also turned up several new species. There are now 11 known species of Heterospathe from the Philippines; four of these are new and are described below.